Liquid crystal display device

ABSTRACT

A liquid crystal display includes an insulation substrate, a plurality of pixels disposed on the insulation substrate, where each pixel has a shape elongated in a horizontal direction, and includes a thin film transistor formation region and a display area; and a reference voltage line extending in a vertical direction along a center of the display area, where the display area includes a single high-gray subpixel area and two low-gray subpixel areas, and the single high-gray subpixel area is positioned between the two low-gray subpixel areas.

This application is a divisional of U.S. patent application Ser. No.14/491,403, filed on Sep. 19, 2014, which claims priority to KoreanPatent Application No. 10-2013-0144856 filed on Nov. 26, 2013, and allthe benefits accruing therefrom under 35 U.S.C. § 119, the contents ofwhich are incorporated by reference herein in its entirety.

BACKGROUND

(a) Field

Exemplary embodiments of the invention relate to a liquid crystaldisplay.

(b) Description of the Related Art

A liquid crystal display (“LCD”) is one of the most widely used types offlat panel displays. The LCD typically includes two display panels, inwhich field generating electrodes such as pixel electrodes and commonelectrodes are provided, and a liquid crystal layer interposed betweenthe two display panels. In such an LCD, a voltage is applied to thefield generating electrodes to generate an electric field in the liquidcrystal layer, which determines the direction of liquid crystalmolecules of the liquid crystal layer, and an image is displayed bycontrolling the polarization of incident light.

Among the LCDs, a vertical alignment (“VA”) mode LCD, in whichlongitudinal axes of liquid crystal molecules are aligned perpendicularto the panels in the absence of an electric field, has been developed.

In the VA mode LCD, a wide viewing angle may be realized by formingcutouts such as minute slits in the field-generating electrodes. Sincethe cutouts and protrusions may determine the tilt directions of theliquid crystal molecules, the tilt directions may be distributed invarious directions using the cutouts and protrusions such that thereference viewing angle is widened.

SUMMARY

In a vertical alignment mode liquid crystal display, where the minuteslits are defined in the pixel electrode including a plurality of branchelectrodes, the response speed of liquid crystal molecules may bedeteriorated due a relationship with other liquid crystal control forcesof the liquid crystal molecule as well as the minute slits, such that atexture may be displayed over time.

Exemplary embodiments of the invention provide a liquid crystal displaywith reduced deterioration of display quality due to texture whileminimizing a reduction of an aperture ratio. The invention also providesa liquid crystal display in which a vertical line stain is notgenerated.

An exemplary embodiment of a liquid crystal display according to theinvention includes: an insulation substrate; a plurality of pixelsdisposed on an insulation substrate, where each pixel has a shapeelongated in a horizontal direction, and includes a thin film transistorformation region and a display area; and a reference voltage lineextending in a vertical direction along a center of the display area,where the display area includes a single high-gray subpixel area and twolow-gray subpixel areas, and the single high-gray subpixel area ispositioned between the two low-gray subpixel areas.

In an exemplary embodiment, the liquid crystal display may furtherinclude a first thin film transistor connected to a high-gray pixelelectrode disposed in the single high-gray subpixel area, a second thinfilm transistor connected to two low-gray pixel electrodes disposed inthe two low-gray subpixel areas, respectively, and a third thin filmtransistor connected to the two low-gray pixel electrodes and thereference voltage line.

In an exemplary embodiment, the reference voltage line may include abranch extending toward the thin film transistor formation region alongan outer region of the display area.

In an exemplary embodiment, each of the single high-gray subpixel areaand the two low-gray subpixel areas may include four domains.

In an exemplary embodiment, the reference voltage line may cross acenter of the single high-gray subpixel area.

In an exemplary embodiment, the display area may include eight domains.

In an exemplary embodiment, the single high-gray subpixel area mayinclude four domains, and each of the two low-gray subpixel areas mayinclude two domains.

In an exemplary embodiment, the single high-gray subpixel area mayinclude three domains, one of the two low-gray subpixel areas mayinclude three domains, and the other of the two low-gray subpixel areasmay include two domains.

In an exemplary embodiment, the eight domains of the display area may bearranged in two rows extending in the horizontal direction and fourcolumns extending in the vertical direction in the display area, and thesingle high-gray subpixel area may include a domain disposed in a secondcolumn and a second row, a domain disposed in a third column and a firstrow, and a domain disposed in the third column and the second row.

In an exemplary embodiment, the liquid crystal display may furtherinclude a first connection disposed along an upper region of the displayarea, wherein the first connection connects the single high-gray pixelelectrode and the first thin film transistor to each other, and a secondconnection disposed along the upper region of the display area, whereinthe third connection connects one of the two low-gray pixel electrodesand the second thin film transistor.

In an exemplary embodiment, each of the first connection and the secondconnection may include a bent end portion bent from an extendingdirection thereof toward the display area, and a length of the bent endportion of each of the first connection and the second connection may bein a range of about 6 micrometers (μm) to about 8 μm.

In an exemplary embodiment, each of the single high-gray pixel electrodeand the two low-gray pixel electrodes may include a plurality of unitpixel electrodes, each unit pixel electrode may include a centerelectrode having a plane shape and a plurality of minute branchesextending from a side of the center electrode, each of the singlehigh-gray subpixel area and the two low-gray subpixel areas may includea common electrode facing the unit pixel electrodes thereof, and anopening may be defined in the common electrode.

An exemplary embodiment of a liquid crystal display according to theinvention includes: an insulation substrate; a plurality of pixelsdisposed on the insulation substrate, where each pixel has a shapeelongated in a horizontal direction, and includes a thin film transistorformation region and a display area; and a reference voltage lineextending in a vertical direction along a center of the display area,where the display area includes a plurality of domains arranged in tworows, one row domain among two row domains is the high-gray subpixelarea, the domains in a first row of the two rows define a high-graysubpixel area of the display area, the domains in a second row of thetwo rows define a low-gray subpixel area of the display area, and thereference voltage line includes a branch extending toward the thin filmtransistor formation region along an outer region of the display area.

In an exemplary embodiment, the liquid crystal display may furtherinclude a first thin film transistor connected to a high-gray pixelelectrode disposed in the high-gray subpixel area, a second thin filmtransistor connected to a low-gray pixel electrode disposed in thelow-gray subpixel area, and a third thin film transistor connected tothe low-gray pixel electrode and the reference voltage line.

In an exemplary embodiment, each of the high-gray subpixel area and thelow-gray subpixel area may include six domains.

In an exemplary embodiment, the reference voltage line may cross acenter of the high-gray subpixel area and the low-gray subpixel area.

In an exemplary embodiment, the high-gray pixel electrode may include aplurality of unit pixel electrodes corresponding to the domains in thehigh-gray pixel area, the low-gray pixel electrode may include aplurality of unit pixel electrodes corresponding to the domains in thelow-gray pixel area, one of the unit pixel electrodes of the high-graypixel electrode in the high-gray subpixel area and one of the unit pixelelectrodes of the low-gray pixel electrode in the low-gray subpixel areamay be disposed adjacent to each other in the vertical direction, and adistance between the unit pixel electrodes disposed adjacent to eachother in the vertical direction may be uniform.

In an exemplary embodiment, the high-gray pixel electrode may include aplurality of unit pixel electrodes corresponding to the domains in thehigh-gray pixel area, the low-gray pixel electrode may include aplurality of unit pixel electrodes corresponding to the domains in thelow-gray pixel area, one of the unit pixel electrodes of the high-graypixel electrode in the high-gray subpixel area and one of the unit pixelelectrodes of the low-gray pixel electrode in the low-gray subpixel areamay be disposed adjacent to each other in the vertical direction, and adistance between the unit pixel electrodes disposed adjacent to eachother in the vertical direction may increase in a direction away fromthe center of the display area toward a side of the display area.

In an exemplary embodiment, a difference between the distance betweenthe unit pixel electrodes disposed adjacent to each other in thevertical direction at the center of the display area and the distancebetween the unit pixel electrodes disposed adjacent to each other in thevertical direction at the side of the display area may be in a range ofabout zero (0) μm to about 3 μm.

In an exemplary embodiment, each of the high-gray pixel electrode andthe low-gray pixel electrode may include a plurality of unit pixelelectrodes, each of the unit pixel electrodes may include a centerelectrode having a plane shape and a plurality of minute branchesextending from a side of the center electrode, each of the high-graysubpixel area and the low-gray subpixel area may include a commonelectrode facing the unit pixel electrodes thereof, and an opening maybe defined in the common electrode.

As described above, in exemplary embodiments of the liquid crystaldisplay including the pixel having an elongated shape in the horizontaldirection, the texture and the portion to be covered by the lightblocking member may be minimized, thereby improving the aperture ratio.In such embodiments, by forming the right-left symmetry of the pixelthat is elongated in the horizontal direction, an occurrence of avertical line stain is effectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the invention will become more apparentby describing in detailed exemplary embodiments thereof with referenceto the accompanying drawings, in which:

FIG. 1 is a block diagram showing an exemplary embodiment of a displaydevice according to the invention;

FIG. 2 is a schematic diagram showing an exemplary embodiment of a pixelof a display device according to the invention;

FIG. 3 is a view showing a connection relationship of pixels of anexemplary embodiment of a display device, according to the invention;

FIG. 4 is a plan view of a pixel electrode and surroundings thereof inan exemplary embodiment of a display device according to the invention;

FIG. 5 is a view of a detailed structure of a pixel of FIG. 4;

FIG. 6 is a view of texture of an exemplary embodiment of a pixel in astructure of FIG. 5;

FIG. 7 is a schematic diagram showing another alternative exemplaryembodiment of a pixel according to the invention;

FIG. 8 is a plan view of a pixel electrode and surroundings thereof inan alternative exemplary embodiment of a display device according to theinvention;

FIG. 9 is a view of texture of an exemplary embodiment of a pixel in astructure of FIG. 8;

FIG. 10 is a plan view of a pixel electrode and surroundings thereof inanother alternative exemplary embodiment of a display device accordingto the invention;

FIG. 11 is a view of texture of an exemplary embodiment of a pixel in astructure of FIG. 10;

FIG. 12 to FIG. 14 are views of a connection structure of an exemplaryembodiment of a pixel electrode according to the invention;

FIG. 15 is a schematic diagram showing an alternative exemplaryembodiment of a pixel of a display device according to the invention;

FIG. 16 is a view of a detailed structure of another alternativeexemplary embodiment a pixel of FIG. 15;

FIG. 17 is a view of texture of an exemplary embodiment of a pixel in astructure of FIG. 16;

FIG. 18 is a cross-sectional view of a position where texture isgenerated according to an electric field in an exemplary embodiment of aliquid crystal display according to the invention;

FIG. 19 to FIG. 22 are views of texture of exemplary embodiments of apixel electrode having various structures, according to the invention;

FIG. 23 to FIG. 27 are equivalent circuit diagrams showing exemplaryembodiments of a pixel according to the invention; and

FIG. 28 is a view showing an exemplary embodiment of a process ofproviding a pretilt angle to liquid crystal molecules using prepolymersthat are polarized by light such as ultraviolet rays.

DETAILED DESCRIPTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be therebetween. In contrast, when an element is referredto as being “directly on” another element, there are no interveningelements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thedisclosure, and will not be interpreted in an idealized or overly formalsense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the claims.

Now, an exemplary embodiment of a display device according to theinvention will be described with reference to FIG. 1.

FIG. 1 is a block diagram showing an exemplary embodiment of a displaydevice according to the invention.

As shown in FIG. 1, an exemplary embodiment of a display device,according to the invention, includes a display panel 300 for displayingan image, a data driver 500 and a gate driver 400 for driving thedisplay panel 300, and a signal controller 600 for controlling the datadriver 500 and the gate driver 400.

The display panel 300 includes a plurality of gate lines G1 to Gn and aplurality of data lines D1 to D(m+1). The plurality of gate lines G1 toGn extend substantially in a transverse direction, and the plurality ofdata lines D1 to D(m+1) extends substantially in a longitudinaldirection, thereby crossing the plurality of gate lines G1 to Gn. Insuch an embodiment, a plurality of reference voltage lines V1 to Vmextending substantially in the longitudinal direction are disposedbetween the plurality of data lines D1 to D(m+1). The reference voltagelines V1 to Vm cross the gate lines G1 to Gn.

Each pixel PX is connected to a corresponding gate line and acorresponding data line. The pixels PX are arranged substantially in amatrix form including a plurality of pixel rows and a plurality of pixelcolumns, and each pixel PX may be a transverse type pixel having a shapeelongated substantially in the horizontal or the transverse directionthat is an extension direction of the gate lines G1 to Gn. As describedabove, the transverse type pixel may include a thin film transistor, aliquid crystal capacitor, and storage capacitor. A control terminal ofthe thin film transistor is connected to the corresponding gate line ofthe gate lines G1 to Gn, an input terminal of the thin film transistoris connected to the corresponding data line of the data lines D1 toD(m+1), and an output terminal of the thin film transistor is connectedto one terminal (a pixel electrode) of the liquid crystal capacitor andone terminal of a storage capacitor. The other terminal of the liquidcrystal capacitor is connected to the common electrode, and the otherterminal of the storage capacitor may be applied with a storage voltage.According to an exemplary embodiment, a channel layer of the thin filmtransistor may include or be made of amorphous silicon, polysilicon, oran oxide semiconductor, for example. The reference voltage lines V1 toVm provide a reference voltage to the pixels PX. In an exemplaryembodiment, the reference voltage has a constant level that is notchanged according to time. In an alternative exemplary embodiment, thereference voltage may have a voltage level that changes according totime.

In an exemplary embodiment of the liquid crystal display according tothe invention, a data line is alternately connected to left and rightpixels PX. In such an embodiment, the data line is connected to thepixel PX positioned at the right side in the first row, is connected tothe pixel PX positioned at the left side in the second row, and isconnected to the pixels PX positioned at the right side in the thirdrow. In an exemplary embodiment, a gate line is connected to all pixelsPX of a pixel row corresponding thereto.

According to such an embodiment, the odd-numbered pixels and theeven-numbered pixels in a pixel column are connected to different datalines, e.g., two adjacent data lines thereof. In such an embodiment,when each data line is applied with the data voltage of the samepolarity during one frame, a polarity inversion displayed at the pixelsPX may appear as a dot inversion.

A number of the data lines D1 to D(m+1) (e.g., m+1) may be greater thana number (m) of the pixel columns by one. In an exemplary embodiment, asshown in FIG. 1, the pixel column does not exist at the left side of thefirst data line D1 such that only the pixel column at the right sidethereof is alternately connected to the first data line D1, and thepixel column does not exist at the right side such that the last dataline, that is, the (m+1)-th data line D(m+1), may only be alternatelyconnected to the pixel column at the left side thereof.

The signal controller 600 operates based on an operation condition ofthe liquid crystal display panel 300 in response to input data and acontrol signal from the outside, for example, a vertical synchronizationsignal, a horizontal synchronization signal, a main clock signal, and adata enable signal, and then generates and outputs image data DAT, agate control signal CONT1, a data control signal CONT2, and a clocksignal based on the input data and the control signal.

The gate control signal CONT1 may include a scanning start signal whichinstructs to start outputting the gate-on voltage, and a gate clocksignal which controls an output timing of the gate-on voltage.

The data control signal CONT2 may include a horizontal synchronizationstart signal which instructs to start inputting the image data DAT, anda load signal which applies a data voltage to the data lines D1 toD(m+1).

The plurality of gate lines G1 to Gn of the display panel 300 areconnected to the gate driver 400, and the gate driver 400 sequentiallyapplies the gate-on voltage Von to the gate lines G1 to Gn based on thegate control signal CONT1 applied from the signal controller 600.

The gate-off voltage is applied during a section of a frame in which thegate-on voltage Von is not applied to the gate lines G1 to Gn.

The plurality of data lines D1 to D(m+1) of the display panel 300 areconnected to the data driver 500, and the data driver 500 receives thedata control signal CONT2 and the image data DAT from the signalcontroller 600. The data driver 500 converts the image data DAT into thedata voltage using gray voltages generated in a gray voltage generator(not shown) and transmits the data voltage to the data lines D1 toD(m+1). The data voltage includes a data voltage of a positive polarityand a data voltage of a negative polarity. The data voltage of thepositive polarity and the data voltage of the negative polarity arealternately applied with reference to a frame, the pixel row, or thepixel column to be driven by the inversion method. The inversion drivingmay be performed to display a motion picture or a still image.

According to an exemplary embodiment, various pixel connectionstructures that are not shown in FIG. 1 may be provided.

Next, a structure of one pixel PX will be schematically described withreference to FIG. 2.

FIG. 2 is a schematic diagram showing a pixel of an exemplary embodimentof a display device according to the invention.

According to an exemplary embodiment of the invention, a pixel PX of thedisplay device is a transverse type pixel having a shape elongatedsubstantially in the horizontal direction. In such an embodiment, thepixel PX includes a thin film transistor formation region TA and adisplay area DA. The pixel electrode of the pixel is disposed in thedisplay area DA, and the image is displayed through liquid crystalmolecules disposed in the display area DA. The thin film transistorformation region TA includes an element and wiring such as a thin filmtransistor for transmitting a voltage to be applied to the pixelelectrode of the display area DA.

In an exemplary embodiment, as shown in FIG. 2, a reference voltage lineV is disposed in the longitudinal direction along an imaginary verticalcenter line of the display area DA in the pixel PX. In such anembodiment, the display area DA is largely divided into three subpixelareas, e.g., one or single high-gray subpixel area H sub and twolow-gray subpixel areas L sub. The high-gray subpixel area H sub ispositioned at a center portion of the pixel PX and the two low-graysubpixel areas L sub are positioned at respective sides of the onehigh-gray subpixel area H sub, as shown in FIG. 2. In such anembodiment, the reference voltage line V passes through the center ofthe high-gray subpixel area H sub in the longitudinal direction.

In an exemplary embodiment, each of the subpixel areas H sub and L subinclude four domains, as shown by dotted lines in FIG. 2. In such anembodiment, each subpixel area is divided into four domains by linesintersecting the center in a transverse direction and a longitudinaldirection. Accordingly, in such an embodiment, the pixel PX includestwelve domains. In such an embodiment, the reference voltage line V ispositioned while dividing twelve the domains in half, and four domainsof the low-gray subpixel area L sub and two domains of the high-graysubpixel area H sub are positioned at each of the left and right sidesof the reference voltage line V. Accordingly, in such an embodiment, theleft part and the right part of the display area DA with reference tothe reference voltage line V display images substantially symmetrical toeach other. In an exemplary embodiment, where the pixel displays animage of the left and right symmetry with reference to the referencevoltage line V, the plurality of pixels PX may output an image as shownin FIG. 3.

FIG. 3 is a view showing a connection relationship of pixels of anexemplary embodiment of a display device according to the invention.

FIG. 3 shows a structure in which each pixel PX outputs an image withleft-right or mirror symmetry with reference to the reference voltageline V corresponding thereto, and the adjacent pixels PX have differentpolarities. In FIG. 3, D refers to the data line.

In an exemplary embodiment, as shown in FIG. 3, each pixel PX isright-left symmetrical, and the adjacent pixels PX are applied with thedata voltages of different polarities. Accordingly, in such anembodiment, although the high-gray subpixels are disposed along a samesubpixel column and the low-gray subpixels are disposed along a samesubpixel column, a luminance difference may not occur and a verticalline stain is not recognized by a viewer.

In an exemplary embodiment, the reference voltage line V crosses thecenter of the pixel PX such that a portion of the high-gray subpixeloverlaps, e.g., is covered by, the reference voltage line V. However, insuch an embodiment, the higher luminance higher than the low-graysubpixel is displayed by the high-gray subpixel such that the luminancedeterioration due to the reference voltage line V is substantially smalland a reduction of the aperture ratio is decreased. In such anembodiment, the reference voltage line V divides the display luminanceto be substantially constant on the right and left of the pixel PX suchthat the display quality may be substantially constantly maintained atthe right and left of the pixel PX.

Next, a structure of the pixel electrode and the reference voltage lineV in the pixel PX will be described with reference to FIG. 4.

FIG. 4 is a plan view of a pixel electrode and surroundings thereof inan exemplary embodiment of a display device according to the invention.

The pixel electrode in a pixel PX includes a high-gray pixel electrode191 a as the pixel electrode of the high-gray subpixel and a low-graypixel electrode 191 b as the pixel electrode of the low-gray subpixel.

Each of the high-gray pixel electrode 191 a and the low-gray pixelelectrode 191 b includes four unit pixel electrodes 198 and 199corresponding to four domains, respectively, and each unit pixelelectrode includes a center electrode 198 and a plurality of minutebranches 199 extending outside from a side of the center electrode 198.The plurality of minute branches 199 may form an angle of about 45degrees with respect to a horizontal direction or a vertical direction,or may form an angle in a range of about 40 degrees to about 50 degreeswith respect to the horizontal direction or the vertical direction.Also, one side of the center electrode 198 and the minute branches 199may be vertical to each other.

Four unit pixel electrodes of the high-gray pixel electrode 191 a andfour unit pixel electrodes the low-gray pixel electrode 191 b areconnected to each other through an extension. In an exemplaryembodiment, as shown in FIG. 4, the center electrode 198 has a sizelarge enough to contact or to define a side of a region where the unitpixel electrode is disposed, but not being limited thereto. In analternative exemplary embodiment, the size of the center electrode 198may be decreased, and the minute branches 199 may be positioned at thecorner of the center electrode 198 to contact or define the side of theregion where the unit pixel electrode is disposed. The extension of theunit pixel electrode extends from the center electrode 198 or the minutebranches 199. Four unit pixel electrodes connected by the extension areapplied with a same voltage. The unit pixel electrodes in a same pixelelectrode, e.g., the high-gray pixel electrode 191 a or the low-graypixel electrode 191 b, are connected to each other through theextension, and are separated from the unit pixel electrodes included inanother pixel electrode, e.g., the low-gray pixel electrode 191 b or thehigh-gray pixel electrode 191 a.

In an exemplary embodiment, openings 72, 73 and 78 are defined in anupper common electrode of one domain region where the unit pixelelectrodes 198 and 199 are positioned as a domain divider. In such anembodiment, the openings in the upper common electrode may be across-shaped opening including a transverse opening 72 and alongitudinal opening 73 crossing the transverse opening 72, and a centeropening 78 positioned at the center of the cross-shaped opening. Thecenter opening 78 may have a polygonal shape including four straightsides respectively positioned at four subregions divided by thecross-shaped opening. In one exemplary embodiment, for example, thecenter opening 78 has a rhombus shape.

In an exemplary embodiment, the openings 72, 73 and 78 corresponding tothe adjacent unit pixel electrodes are not connected to each other. Inan alternative exemplary embodiment, the openings 72, 73 and 78 in theadjacent unit pixel electrodes may be connected to each other.

In the structure in which a low-gray pixel electrode 191 b, a high-graypixel electrode 191 a and a low-gray pixel electrode 191 b aresequentially arranged, the reference voltage line 178 crosses the centerof the high-gray pixel electrode 191 a positioned at the center of thepixel in the longitudinal direction.

The entire structure of the pixel including the pixel electrode, thecommon electrode and the reference voltage line described above will bedescribed in greater detail with reference to FIG. 5.

FIG. 5 is a view of the detailed structure of the pixel of FIG. 4.

Firstly, in an exemplary embodiment of a display device, a plurality ofgate lines 121 is disposed on an insulation substrate (not shown) of alower panel thereof.

The gate lines 121 extend substantially in the transverse direction andinclude a first gate electrode 124 a, a second gate electrode 124 b anda third gate electrode 124 c protruding and extending upwardly from thegate line 121. In such an embodiment, the third gate electrode 124 cextends and expands upwardly from the gate line 121, and the first gateelectrode 124 a and the second gate electrode 124 b extend from thethird gate electrode 124 c. The first gate electrode 124 a and thesecond gate electrode 124 b may be defined at a same expanded regionfrom the third gate electrode 124 c. In such an embodiment, the gateline 121 may include a curved portion that is periodically curved from amain line extending in the transverse direction.

A gate insulating layer is disposed on the gate line 121, and a firstsemiconductor 154 a, a second semiconductor 154 b and a thirdsemiconductor 154 c are disposed on the first gate electrode 124 a, thesecond gate electrode 124 b and the third gate electrode 124 c,respectively.

A data conductor including a data line 171, a first drain electrode 175a, a second drain electrode 175 b, a third source electrode 173 c, athird drain electrode 175 c and the reference voltage line 178 isdisposed on the first semiconductor 154 a, the second semiconductor 154b, third semiconductor 154 c and the gate insulating layer.

The data line 171 extends substantially in the longitudinal directionand includes a first source electrode 173 a and a second sourceelectrode 173 b respectively extending from a main line of the data line171 toward the first and second gate electrodes 124 a and 124 b.

The reference voltage line 178 includes a main line 178 a extendingsubstantially parallel to the data line 171 and a branch 178 b extendingfrom the main line 178 a and substantially parallel to the gate line121. The branch 178 b extends to a thin film transistor formation regionTA along an outer region of the display area, and one end of the branch178 b defines the third drain electrode 175 c.

In such an embodiment, the first drain electrode 175 a faces the firstsource electrode 173 a, the second drain electrode 175 b faces thesecond source electrode 173 b, and the third drain electrode 175 c facesthe third source electrode 173 c. The third source electrode 173 c isconnected to the second drain electrode 175 b.

The first gate electrode 124 a, the first source electrode 173 a and thefirst drain electrode 175 a collectively define a first thin filmtransistor along with the first semiconductor 154 a, the second gateelectrode 124 b, the second source electrode 173 b and the second drainelectrode 175 b collectively define a second thin film transistor alongwith the second semiconductor 154 b, and the third gate electrode 124 c,the third source electrode 173 c and the third drain electrode 175 ccollectively define a third thin film transistor along with the thirdsemiconductor 154 c. In such an embodiment, the data voltage is appliedthrough the source electrode of the first thin film transistor and thesecond thin film transistor, and the reference voltage is appliedthrough the source electrode of the third thin film transistor.

A passivation layer is disposed on the data conductor and a pixelelectrode is disposed on the passivation layer.

In such an embodiment, each pixel electrode includes one high-gray pixelelectrode 191 a and two low-gray pixel electrodes 191 b as shown in FIG.4.

The first drain electrode 175 a of the first thin film transistor isconnected to the high-gray pixel electrode 191 a through a first contacthole 185 a. In an exemplary embodiment, as shown in FIG. 5, the firstdrain electrode 175 a of the first thin film transistor is connected tothe high-gray pixel electrode 191 a through a first connection 195 adisposed in an upper region of the pixel (the display area). The firstconnection 195 a includes a bent end portion connected to one unit pixelelectrode of the high-gray pixel electrode 191 a. In an exemplaryembodiment, the first connection 195 a may have a linear structure, andis directly connected to the center electrode 198 of the high-gray pixelelectrode 191 a, as shown in FIG. 14. Referring to FIG. 12 and FIG. 13,in an alternative exemplary embodiment, where the first connection 195 ainclude a bent end portion connected to one unit pixel electrode of thehigh-gray pixel electrode 191 a, a length of the bent end portion of thefirst connection 195 a bent toward the high-gray pixel electrode 191 amay be in a range of about 6 micrometers (μm) to about 8 μm.

The second drain electrode 175 b of the second thin film transistor isconnected to two low-gray pixel electrodes 191 b through a secondconnection 195 b and a third connection 195 c, respectively, via asecond contact hole 185 b. The center electrode 198 of the low-graypixel electrode 191 b closer to the second thin film transistor isconnected to the second drain electrode 175 b through the secondconnection 195 b. The low-gray pixel electrode 191 b far from the secondthin film transistor is connected to the second drain electrode 175 bthrough the third connection 195 c disposed along the upper region ofthe pixel (the display area). In an exemplary embodiment, the thirdconnection 195 c includes a bent end portion connected to one unit pixelelectrode of the low-gray pixel electrode 191 b. In an alternativeexemplary embodiment, the third connection 195 c is not divided into twoportions by bending but linearly extends to be connected to the centerelectrode 198 of the low-gray pixel electrode 191 b as shown in FIG. 14.Referring to FIG. 12 and FIG. 13, in an exemplary embodiment, where thethird connection 195 c includes a bent end portion connected to one unitpixel electrode of the low-gray pixel electrode 191 b, a length of thebent end portion of the third connection 195 c bent toward the low-graypixel electrode 191 b may be in a range of about 6 μm to about 8 μm.

Next, a common electrode facing the pixel electrode and which receives acommon voltage is disposed on an insulation substrate of an upper panelof the display device. In such an embodiment, the openings 72, 73 and 78are defined in the common electrode, as shown in FIG. 4. According to anexemplary embodiment, the common electrode may include a protrusion asthe domain divider.

In such an embodiment, the display device includes a liquid crystallayer interposed between the lower panel and the upper panel, and theliquid crystal layer includes liquid crystal molecules having negativedielectric anisotropy. The liquid crystal molecules may be aligned suchthat longitudinal axes thereof are substantially perpendicular to thetwo display panels when an electric field is not generated therein.

In such an embodiment, when the data voltage is transmitted to the pixelPX, the data voltage is applied as it is to the high-gray pixelelectrode 191 a through the first thin film transistor. In such anembodiment, the two low-gray pixel electrodes 191 b are applied with amiddle voltage between the data voltage applied through the second thinfilm transistor and the reference voltage applied through the third thinfilm transistor. As a result, the high-gray pixel electrode 191 a andtwo low-gray pixel electrodes 191 b are applied with the voltages of thedifferent levels.

The high-gray and low-gray pixel electrodes 191 a and 191 b applied withthe data voltages of the different levels generate an electric fieldalong with a common electrode of the upper panel such that theorientation of the liquid crystal molecules of the liquid crystal layerbetween the two electrodes is determined. When the orientation of theliquid crystal molecules of the liquid crystal layer between the twoelectrodes is determined, the inclination direction of the liquidcrystal molecules may be firstly determined by a horizontal componentgenerated by a gap where the pixel electrode is not positioned and theside of the opening of the common electrode that distorts the mainelectric field substantially perpendicular to the surface of the displaypanel. The horizontal component of the main electric field issubstantially perpendicular to the side of the unit pixel electrode andthe opening, and the liquid crystal molecules are inclined in thedirection substantially vertical to the sides thereof.

A portion where texture is generated in the pixel having the structureof FIG. 4 and FIG. 5 will be described with reference to FIG. 6.

FIG. 6 is a view showing texture of an exemplary embodiment of a pixelin a structure of FIG. 5.

In FIG. 6, the texture is shown in the portion indicated by T. Thisportion is below the low-gray pixel electrode 191 b and above the branch178 b of the reference voltage line 178. In general, the texture mainlyappears on the circumference (up/down/right/left) of the low-gray pixelelectrode 191 b. In the pixel structure of an exemplary embodiment ofthe invention, as shown in FIG. 6, the texture is only recognized underthe low-gray pixel electrode 191 b closer to the thin film transistorformation region TA among two low-gray pixel electrodes 191 b such thatthe formation of the texture is reduced.

Exemplary embodiments, in which one display area DA is divided intotwelve domains, are described above.

Next, exemplary embodiments in which one display area DA is divided intoeight domains will be described with reference to FIG. 7 to FIG. 11.

FIG. 7 is a schematic diagram of a pixel of an alternative exemplaryembodiment of a display device, according to the invention.

In an exemplary embodiment, a pixel PX is the transverse type pixelhaving a shape elongated substantially in the horizontal direction witha total of eight domains. The eight domains are arranged in thehorizontal direction and the vertical direction with 2 rows and 4columns.

In such an embodiment, the pixel PX generally includes the thin filmtransistor formation region TA and the display area DA. The pixelelectrode is disposed in the display area DA, and the image is displayedthrough the liquid crystal molecules positioned at the display area DA.In such an embodiment, an element and wiring such as a thin filmtransistor transmitting the voltage to be applied to the pixel electrodeof the display area DA are disposed in the thin film transistorformation region TA.

In an exemplary embodiment of the pixel PX, as shown in FIG. 7, thereference voltage line V is positioned in the longitudinal directionalong the center of the display area DA. The reference voltage line Vvertically extends while dividing eight domains into two regions, eachof which includes four domains. In such an embodiment, the display areaDA is divided into three subpixel areas, and includes one high-graysubpixel area H sub and two low-gray subpixel areas L sub.

FIG. 7 does not show positions of the high-gray subpixel area H sub andthe two low-gray subpixel areas L sub in the pixel PX. In an exemplaryembodiment, the high-gray subpixel area H sub may be positioned at thecenter and the low-gray subpixel areas L sub may be positioned at sidesthereof, but not being limited thereto. In an alternative exemplaryembodiment, the positions of the high-gray subpixel area H sub and thetwo low-gray subpixel areas L sub may be variously modified as shown inFIG. 8 and FIG. 10.

Firstly, an exemplary embodiment shown in FIG. 8 will be described.

FIG. 8 is a plan view of a pixel electrode and surroundings thereof inan alternative exemplary embodiment of a display device according to theinvention.

In an exemplary embodiment, as shown in FIGS. 7 and 8, four domainsamong a total of eight domains correspond to the high-gray subpixel areaH sub and the remaining four domains among a total of eight domainscorrespond to two low-gray subpixel areas L sub. In such an embodiment,four domains positioned at the center correspond to the high-graysubpixel area H sub, and two domains in each side portion correspond tothe low-gray subpixel areas L sub. Each of the two low-gray subpixelareas L sub are defined by two domains. In such an embodiment, thereference voltage line V crosses the center of the high-gray subpixelarea H sub in the longitudinal direction. In FIG. 8, the high-gray pixelelectrode included in the high-gray subpixel area H sub is indicated by191 a, and the low-gray pixel electrode of the low-gray subpixel area Lsub is indicated by 191 b.

The high-gray subpixel area H sub includes four domains, and eachlow-gray subpixel area L sub includes two domains. Each domain isindicated by a dotted line in FIG. 7, and the dotted line in FIG. 8divides the subpixel areas. In such an embodiment, the reference voltageline V is disposed in the vertical direction through the center of thepixel PX while dividing eight domain into half, and one low-graysubpixel area L sub and two domains of the high-gray subpixel area H arepositioned at the right side of the reference voltage line V, and theother low-gray subpixel area L sub and the remaining two domains of thehigh-gray subpixel area H are positioned at the left side of thereference voltage line V. As a result, an image displayed by the pixelPX have a right-left symmetry with reference to the reference voltageline V.

The pixel electrode positioned in the pixel PX includes the high-graypixel electrode 191 a as the pixel electrode of the high-gray subpixeland the low-gray pixel electrode 191 b as the pixel electrode of thelow-gray subpixel.

The high-gray pixel electrode 191 a includes four unit pixel electrodes198 and 199 corresponding to four domains, respectively, and each of thetwo low-gray pixel electrodes 191 b include two unit pixel electrodes198 and 199. A total number of the unit pixel electrodes 198 and 199included in two low-gray pixel electrodes 191 b is 4.

Each unit pixel electrode includes the center electrode 198 and theminute branches 199 extending outwardly from the side of the centerelectrode 198. The minute branches 199 may form an angle of about 45degrees with respect to a horizontal direction or a vertical direction,or may form an angle in a range of about 40 degrees to about 50 degrees.Also, one side of the center electrode 198 and the minute branches 199may be substantially vertical to each other.

The unit pixel electrodes of the high-gray pixel electrode 191 a and thelow-gray pixel electrode 191 b may be connected to each other throughthe extension. In an exemplary embodiment, as shown in FIG. 8, thecenter electrode 198 has a size large enough to contact or define theside of the region where the unit pixel electrode is disposed. In analternative exemplary embodiment, the size of the center electrode 198may be decreased, and the minute branches 199 may be positioned at thecorner of the center electrode 198 to contact or define the side of theregion where the unit pixel electrode is disposed. The extension of theunit pixel electrode extends from the center electrode 198 or the minutebranches 199. The unit pixel electrodes connected to each other by theextension are applied with the same voltage. The unit pixel electrodesincluded in a pixel electrode, e.g., the high-gray pixel electrode 191 aor the low-gray pixel electrode 191 b, are connected to each otherthrough the extension, and are separated or spaced apart from the unitpixel electrodes included in the other pixel electrodes, e.g., thelow-gray pixel electrode 191 b or the high-gray pixel electrode 191 a.

In an exemplary embodiment, openings 72, 73 and 78 are defined in anupper common electrode of one domain region where the unit pixelelectrodes 198 and 199 are positioned as domain dividers. In such anembodiment, the opening in the upper common electrode may be across-shaped opening including a transverse opening 72, a longitudinalopening 73 crossing the transverse opening 72, and, a center opening 78positioned at the center of the cross-shaped opening. The center opening78 may have the polygonal shape including four straight sidesrespectively positioned at four sub-regions divided by the cross-shapedopening. In one exemplary embodiment, for example, the center opening 78has a rhombus shape.

In an exemplary embodiment, the openings 72, 73 and 78 corresponding tothe adjacent unit pixel electrodes are not connected to each other. Inan alternative exemplary embodiment, the adjacent openings 72, 73 and 78may be connected to each other.

In the structure in which the low-gray pixel electrode 191 b, thehigh-gray pixel electrode 191 a, and the low-gray pixel electrode 191 bare sequentially arranged, the reference voltage line 178 crosses thecenter of the high-gray pixel electrode 191 a positioned at the centerof the pixel in the longitudinal direction.

In an exemplary embodiment, as shown in FIG. 8, a size of the unit pixelelectrodes 198 and 199, each of which defines a domain, may be differentfrom each other. In such an embodiment, the size of the unit pixelelectrodes 198 and 199 included in the low-gray pixel electrode 191 bmay be larger than the size the unit pixel electrodes 198 and 199included in the high-gray pixel electrode 191 a. In an exemplaryembodiment, in which the high-gray pixel electrode 191 a and thelow-gray pixel electrode 191 b have a different number of unit pixelelectrodes, the size of each unit pixel electrodes may be different fromeach other such that areas occupied by the high-gray pixel electrode 191a and the low-gray pixel electrode 191 b may be substantially the sameor similar to each other.

The portion where the texture is generated in the pixel having thestructure of FIG. 8 will be described with reference to FIG. 9.

FIG. 9 is a view showing texture of an exemplary embodiment of a pixelin a structure of FIG. 8.

In FIG. 9, the texture is shown in the portion indicated by T. Thisportion is below the low-gray pixel electrode 191 b and above the branch178 b of the reference voltage line 178. In general, the texture mainlyappears on the circumference (up/down/right/left) of the low-gray pixelelectrode 191 b. In the pixel structure of an exemplary embodiment ofthe invention, as shown in FIG. 9, the texture is recognized only underthe low-gray pixel electrode 191 b closer to the thin film transistorformation region TA among two low-gray pixel electrodes 191 b such thatthe formation of the texture is reduced.

Next, an alternative exemplary embodiment having an asymmetric structurein which the high-gray pixel electrode 191 a includes three unit pixelelectrodes 198 and 199 will be described with reference to FIG. 10.

FIG. 10 is a plan view of a pixel electrode and surroundings thereof inanother alternative exemplary embodiment of a display device accordingto the invention.

In an exemplary embodiment, as shown in FIG. 10, three domains among atotal of eight domains define the high-gray subpixel area H sub, and theremaining five domains defines two low-gray subpixel areas L sub. Insuch an embodiment, three domains positioned at the center correspond toone high-gray subpixel area H sub, and the remaining five domainspositioned at both sides correspond to two low-gray subpixel areas Lsub. Each domain is divided by the dotted line in FIG. 7, and the dottedline in FIG. 10 divides the subpixel areas.

In an exemplary embodiment, as shown in FIG. 10, three domains includedin the high-gray subpixel area H sub include two domains of a lower rowand one domain of an upper row. In such an embodiment, the left low-graysubpixel area L sub includes three domains, and the right low-graysubpixel area L sub includes two domains.

In such an embodiment, the reference voltage line 178 crosses the centerof eight domains in the longitudinal direction. The reference voltageline 178 extends while dividing two domains of the lower row among threedomains of the high-gray subpixel area H sub. The high-gray subpixelarea H sub has an asymmetric structure with respect to the referencevoltage line 178, however two low-gray subpixel areas L sub may existsides (e.g., left and right sides) of the reference voltage line 178,respectively. In such an embodiment, although two low-gray subpixelareas L sub have the asymmetrical structure, the two low-gray subpixelareas L sub are positioned adjacent to only one side of the referencevoltage line 178, that is, the low-gray subpixel area L of the left sideis spaced apart from the reference voltage line 178.

In FIG. 10, the high-gray pixel electrode included in the high-graysubpixel area H sub is indicated by 191 a, and the low-gray pixelelectrode of the low-gray subpixel area L sub is indicated by 191 b.

The pixel electrode positioned in one pixel PX includes the high-graypixel electrode 191 a as the pixel electrode of the high-gray subpixeland the low-gray pixel electrode 191 b as the pixel electrode of thelow-gray subpixel.

The high-gray pixel electrode 191 a includes three unit pixel electrodes198 and 199 corresponding to three domains, respectively, and twolow-gray pixel electrodes 191 b respectively include three and two unitpixel electrodes 198 and 199. The total number of unit pixel electrodes198 and 199 included in two low-gray pixel electrodes 191 b is 5.

Each unit pixel electrode includes the center electrode 198 and theminute branches 199 extending outwardly from the side of the centerelectrode 198. The minute branches 199 may form an angle of about 45degrees with respect to a horizontal direction or a vertical direction,or may form an angle in a range of about 40 degrees to about 50 degrees.Also, one side of the center electrode 198 and the minute branches 199may be substantially vertical to each other.

The unit pixel electrodes of the high-gray pixel electrode 191 a and thelow-gray pixel electrode 191 b may be connected to each other throughthe extension. In an exemplary embodiment, as shown in FIG. 10, thecenter electrode 198 has a size large enough to contact or define theside of the region where the unit pixel electrode is disposed. In analternative exemplary embodiment, the size of the center electrode 198may be decreased, and the minute branches 199 may be positioned at thecorner of the center electrode 198 to contact or define the side of theregion where the unit pixel electrode is disposed. The extension of theunit pixel electrode extends from the center electrode 198 or the minutebranches 199. The unit pixel electrodes connected by the extension areapplied with the same voltage. The unit pixel electrodes included in apixel electrode, e.g., the high-gray pixel electrode 191 a or thelow-gray pixel electrode 191 b, are connected to each other through theextension, and are separated or spaced apart from the unit pixelelectrodes included in the other pixel electrodes, e.g., the low-graypixel electrode 191 b or the high-gray pixel electrode 191 a.

In an exemplary embodiment, openings 72, 73 and 78 are defined in anupper common electrode of one domain region where the unit pixelelectrodes 198 and 199 are positioned as domain dividers. In anexemplary embodiment, the openings in the upper common electrode may bea cross-shaped opening including a transverse opening 72, a longitudinalopening 73 crossing the transverse opening 72, and a center opening 78positioned at the center of the cross-shaped opening. The center opening78 may have the polygonal shape including four straight sidesrespectively positioned at four sub-regions divided by the cross-shapedopening. In one exemplary embodiment, for example, the center opening 78has rhombus shape.

In an exemplary embodiment, the openings 72, 73 and 78 corresponding tothe adjacent unit pixel electrodes and are not connected to each other.In an alternative exemplary embodiment, the adjacent openings 72, 73,and 78 may be connected to each other.

In the structure in which a low-gray pixel electrode 191 b, a high-graypixel electrode 191 a, and a low-gray pixel electrode 191 b aresequentially arranged, the reference voltage line 178 crosses the centerof the high-gray pixel electrode 191 a positioned at the center of thepixel in the longitudinal direction.

The portion where the texture is generated in the pixel having thestructure of FIG. 10 will be described with reference to FIG. 11.

FIG. 11 is a view showing texture of an exemplary embodiment of a pixelin a structure of FIG. 10.

In FIG. 11, the texture is shown in the portion indicated by T. Thisportion is below the low-gray pixel electrode 191 b and above the branch178 b of the reference voltage line 178. In general, the texture mainlyappears on the circumference (up/down/right/left) of the low-gray pixelelectrode 191 b. In the pixel structure of an exemplary embodiment ofthe invention, the texture is recognized only under the low-gray pixelelectrode 191 b closer to the thin film transistor formation region TAamong two low-gray pixel electrodes 191 b such that the formation of thetexture is reduced.

In an exemplary embodiment of FIG. 10, two unit pixel electrodes amongthe high-gray pixel electrode 191 a are positioned at the lower row. Insuch an embodiment, where the texture is generated at the lower leftregion of the pixel PX and near the low-gray pixel electrode 191 b, awidth of the lower row on the left side is greater than a width of thelower row on the right side such that the size of the texture is furtherreduced, that is, the size of the texture shown in FIG. 11 may besmaller than the size of the texture shown in FIG. 9.

In the above, the texture generated near the low-gray pixel electrode191 b was described.

Hereinafter, a generation degree of the texture according to theconnection structure of the connection 195, in which each unit pixelelectrode 198 and 199 is connected to the drain electrode of the thinfilm transistor, will be described with reference to In FIG. 12 to FIG.14.

FIG. 12 to FIG. 14 are views of a connection structure of an exemplaryembodiment of a pixel electrode according to the invention.

FIG. 12 to FIG. 14 includes a description of the structure of the pixelelectrode in photographs.

In an exemplary embodiment, as shown in FIG. 12 and FIG. 13, theconnection 195 connected to the unit pixel electrode 198 and 199 has alinear structure. In FIG. 14, a connection 195′ connected to the unitpixel electrode 198 and 199 has two bent structure (hereinafter, a dualbent connection 195′).

As shown by the texture of FIG. 14 and the texture of FIG. 12, thetexture near the connection 195 is substantially decreased in theexemplary embodiment of FIG. 12. That is, the texture is less generatedin an embodiment including the connection 195 in a linear structure(hereinafter, a linear connection 195) rather than the dual bentconnection 195′.

FIG. 12 and FIG. 13 show embodiments including the linear connection 195disposed apart from the unit pixel electrode 198 and 199 by differentdistances, that is, the linear connection 195 includes a bent portionextending from an extending direction thereof toward the unit pixelelectrode 198 and 199 to be connected thereto. In FIG. 13, an exemplaryembodiment including the linear connection 195 disposed apart from theunit pixel electrode 198 and 199 with a distance longer by about 1 μmthan the connection 195 of the exemplary embodiment shown in FIG. 12 inthe left side of FIG. 13, and an exemplary embodiment of the linearconnection 195 disposed apart from the unit pixel electrode 198 and 199with a distance longer by about 2 μm than the connection 195 of theexemplary embodiment shown in FIG. 12 is shown in the right side of FIG.13. Here, a reference distance, with which the connection disposed apartfrom the unit pixel electrode 198 and 199, that is, the connection 195of the exemplary embodiment shown in FIG. 12, may be about 6 μm. Asshown in FIG. 12 and FIG. 13, as the distance of the connection 195 fromthe unit pixel electrode 198 and 199 (or the length of the bent endportion of the connection 195) is increased, the texture is decreasedwhile the position of the unit pixel electrode is farther from theboundary of the domain. However, when the unit pixel electrode ispositioned substantially inwardly, the region of the liquid crystalmolecules that are not effectively controlled is increased. Accordingly,in an exemplary embodiment, the distance of the connection may beincreased up to about 2 μm from the reference distance as shown in FIG.13. In an exemplary embodiment, the distance of the connection 195 fromthe unit pixel electrode 198 and 199 may be in the range of about 6 μmto about 8 μm, as described above.

Next, another exemplary embodiment of the invention will be describedwith reference to FIG. 15.

FIG. 15 is a schematic diagram of another alternative exemplaryembodiment of a pixel of a display device according to the invention.

In an exemplary embodiment, the pixel PX is the transverse type pixelhaving a shape elongated substantially in the horizontal direction. Insuch an embodiment, the pixel PX includes the thin film transistorformation region TA and the display area DA. The pixel electrode isdisposed in the display area DA and displays the image through theliquid crystal molecules disposed in the display area DA. In such anembodiment, the element and the wiring such as the thin film transistorthat transmits the voltage to be applied to the pixel electrode of thedisplay area DA are disposed in the thin film transistor formationregion TA.

In an exemplary embodiment, as shown in FIG. 15, the pixel PX includesthe reference voltage line V positioned in the vertical direction at thecenter of the display area DA. In such an embodiment, the display areaDA is divided into two subpixel areas including one high-gray subpixelarea H sub and one low-gray subpixel area L sub. The high-gray subpixelarea H sub and the low-gray subpixel area L sub extend substantially inthe vertical direction. In an exemplary embodiment, as shown in FIG. 15,the high-gray subpixel area H sub is positioned at the upper side in thepixel PX, and the low-gray subpixel area L sub is positioned at thelower side in the pixel PX. As a result, the reference voltage line Vcrosses the center of the high-gray subpixel area H sub and the low-graysubpixel area L sub in the vertical or the longitudinal direction.

In an exemplary embodiment, each of the subpixel areas H sub and L subincludes six domains. Each domain is divided by the dotted line in FIG.15, and the solid line indicates the boundary of the high-tray andlow-gray subpixel areas H sub and L sub. In such an embodiment, thesubpixel areas are divided into upper and lower parts. In an exemplaryembodiment, the pixel PX includes twelve domains, and each subpixel areaH sub or L sub includes six domains. According to an exemplaryembodiment, the pixel PX may be divided into an even-number of domains,e.g., 12. Also, the reference voltage line V is positioned whiledividing twelve domains, and the low-gray subpixel area L sub and thehigh-gray subpixel area H sub are divided into half by the referencevoltage line V. As a result, an image display by the pixel may have theright-left symmetry with reference to the reference voltage line V.

The entire structure of the pixel including the pixel electrode, thecommon electrode and the reference voltage line will be described withreference to FIG. 16.

FIG. 16 is a view of a detailed structure of an exemplary embodiment ofa pixel of FIG. 15.

Firstly, referring to the lower panel of the display device, a pluralityof gate lines 121 are positioned on an insulation substrate of the lowerpanel.

The gate line 121 extends substantially in the horizontal or transversedirection and includes a first gate electrode 124 a, a second gateelectrode 124 b and a third gate electrode 124 c protruding andextending upwardly from the gate line 121. In such an embodiment, thethird gate electrode 124 c extends and expands upwardly from the gateline 121, and the first gate electrode 124 a and the second gateelectrode 124 b extend from the third gate electrode 124 c. The firstgate electrode 124 a and the second gate electrode 124 b may include anexpanded portion. In such an embodiment, the gate line 121 may include acurved portion that is periodically curved from a main line extendingsubstantially in the transverse direction.

A gate insulating layer is disposed on the gate line 121, and a firstsemiconductor 154 a, a second semiconductor 154 b and a thirdsemiconductor 154 c are respectively disposed on the first gateelectrode 124 a, the second gate electrode 124 b and the third gateelectrode 124 c thereon.

A data conductor including a data line 171, a first drain electrode 175a, a second drain electrode 175 b, a third source electrode 173 c, athird drain electrode 175 c and a reference voltage line 178 is disposedon the first semiconductor 154 a, the second semiconductor 154 b, thethird semiconductor 154 c and the gate insulating layer.

The data line 171 extends substantially in the longitudinal direction,and includes a first source electrode 173 a and a second sourceelectrode 173 b respectively extending from a main line of the data line171 toward the first and second gate electrodes 124 a and 124 b.

The reference voltage line 178 includes a main line 178 a extendingsubstantially parallel to the data line 171 and a branch 178 b extendingfrom the main line 178 a and substantially parallel to the gate line121. The branch 178 b extends to a thin film transistor formation regionTA along an outer region of the display area, and one end of the branch178 b defines the third drain electrode 175 c.

In such an embodiment, the first drain electrode 175 a faces the firstsource electrode 173 a, the second drain electrode 175 b faces thesecond source electrode 173 b, and the third drain electrode 175 c facesthe third source electrode 173 c. The third source electrode 173 c isconnected to the second drain electrode 175 b.

The first gate electrode 124 a, the first source electrode 173 a and thefirst drain electrode 175 a collectively define a first thin filmtransistor along with the first semiconductor 154 a, the second gateelectrode 124 b, the second source electrode 173 b and the second drainelectrode 175 b collectively define a second thin film transistor alongwith the second semiconductor 154 b, and the third gate electrode 124 c,the third source electrode 173 c and the third drain electrode 175 ccollectively define a third thin film transistor along with the thirdsemiconductor 154 c. In such an embodiment, the data voltage is appliedthrough the source electrode of the first thin film transistor and thesecond thin film transistor, and the reference voltage is appliedthrough the source electrode of the third thin film transistor.

A passivation layer is disposed on the data conductor, and a pixelelectrode is disposed on the passivation layer.

In such an embodiment, the pixel electrode positioned in a pixel PXincludes the high-gray pixel electrode 191 a as the pixel electrode ofthe high-gray subpixel, and the low-gray pixel electrode 191 b as thepixel electrode of the low-gray subpixel. The pixel electrode includesone high-gray pixel electrode 191 a and one low-gray pixel electrode 191b.

Each of the high-gray pixel electrode 191 a and the low-gray pixelelectrode 191 b include six unit pixel electrodes 198 and 199corresponding to six domains, and each unit pixel electrode includes thecenter electrode 198 and the minute branches 199 extending outwardlyfrom the side of the center electrode 198. The minute branches 199 mayform an angle of about 45 degrees with respect to a horizontal directionor a vertical direction, or may form an angle in a range of about 40degrees to about 50 degrees. Also, one side of the center electrode 198and the minute branches 199 may be substantially vertical to each other.

Six unit pixel electrodes of the high-gray pixel electrode 191 a or thelow-gray pixel electrode 191 b are arranged in the vertical directionwith a line and are connected through the extension. In an exemplaryembodiment of FIG. 16, the center electrode 198 has a size large enoughto contact or define the side of the region where the unit pixelelectrode is disposed, but not being limited thereto. In an alternativeexemplary embodiment, the size of the center electrode 198 may bedecreased, and the minute branches 199 may be positioned at the cornerof the center electrode 198. The extension of the unit pixel electrodeextends from the center electrode 198 or the minute branches 199. Sixunit pixel electrodes connected by the extension are applied with thesame voltage. The unit pixel electrodes included in one of the high-graypixel electrode 191 a and the low-gray pixel electrode 191 b areconnected to each other through the extension, and are separated orspaced apart from the unit pixel electrodes included in the other of thehigh-gray pixel electrode 191 a and the low-gray pixel electrode 191 b.

The first drain electrode 175 a of the first thin film transistor isconnected to the high-gray pixel electrode 191 a through the firstcontact hole 185 a. In an exemplary embodiment, as shown in FIG. 16, thefirst connection 195 a extends in the left side to be connected to thehigh-gray pixel electrode 191 a.

The second drain electrode 175 b of the second thin film transistor isconnected to the low-gray pixel electrode 191 b through the secondcontact hole 195 b. In an exemplary embodiment, as shown in FIG. 16, thelow-gray pixel electrode 191 b is connected through the secondconnection 195 b, and the second connection 195 b extends in the leftside to be connected to the low-gray pixel electrode 191 b. The thirdthin film transistor connects the second drain electrode 175 b of thesecond thin film transistor and the reference voltage line 178 to changethe level of the data voltage applied to the low-gray pixel electrode191 b.

Next, referring to the upper panel of the display device, a commonelectrode that faces the pixel electrode and receives a common voltageis disposed on an insulation substrate of the upper panel.

In an exemplary embodiment, openings 72, 73 and 78 may be defined in anupper common electrode of one domain region where the unit pixelelectrodes 198 and 199 are positioned as a domain divider. In such anembodiment, the openings in the upper common electrode may be across-shaped opening including a transverse opening 72, a longitudinalopening 73 crossing the transverse opening 72, and, a center opening 78positioned at the center of the cross-shaped opening may be furtherincluded. The center opening 78 may have the polygonal shape includingfour straight sides respectively positioned at four sub-regions dividedby the cross-shaped opening. In one exemplary embodiment, for example,the center opening 78 has a rhombus shape.

In an exemplary embodiment, the openings 72, 73, and 78 corresponding tothe adjacent unit pixel electrodes are not connected to each other. Inan alternative exemplary embodiment, the adjacent openings 72, 73 and 78may be connected to each other.

According to an exemplary embodiment, the common electrode may include aprotrusion as the domain divider.

A liquid crystal layer interposed between the lower panel and the upperpanel includes liquid crystal molecules having negative dielectricanisotropy. The liquid crystal molecules may be aligned such thatlongitudinal axes thereof are disposed substantially perpendicular tothe upper and lower display panels when an electric field is notgenerated therein.

When the data voltage is transmitted to the pixel PX, the data voltageis applied to the high-gray pixel electrode 191 a through the first thinfilm transistor as it is. In such an embodiment, the low-gray pixelelectrode 191 b is applied with a middle voltage between the datavoltage applied through the second thin film transistor and thereference voltage through the third thin film transistor. As a result,the high-gray pixel electrode 191 a and the low-gray pixel electrode 191b are applied with the voltages having different levels.

The high-gray and low-gray pixel electrodes 191 a and 191 b applied withthe data voltages of the different levels generate an electric fieldalong with a common electrode of the upper panel such that theorientation of the liquid crystal molecules of the liquid crystal layerbetween two electrodes is determined. When the orientation of the liquidcrystal molecules of the liquid crystal layer between two electrodes isdetermined, the inclination direction of the liquid crystal moleculesmay be firstly determined by a horizontal component generated by a gapwhere the pixel electrode is not positioned, and the side of the openingof the common electrode that distorts the main electric fieldsubstantially vertical to the surface of the display panel. Thehorizontal component of the main electric field is almost perpendicularto the side of the unit pixel electrode 198 and 199 and the openings 72,73, and 78, and the liquid crystal molecules are inclined in thedirection substantially perpendicular to the sides thereof.

In the structure in which the high-gray pixel electrode 191 a and thelow-gray pixel electrode 191 b are arranged in the upper and lowerportions of the pixel, respectively, the reference voltage line 178crosses the center of the high-gray pixel electrode 191 a and thelow-gray pixel electrode 191 b in the vertical direction, thereby havingthe symmetrical structure.

A portion where a texture is generated in the pixel having the structureof FIG. 16 will be described with reference to FIG. 17.

FIG. 17 is a view showing texture of an exemplary embodiment a pixel ina structure of FIG. 16.

In FIG. 17, the texture is shown in the portion indicated by T. As shownin FIG. 17, the texture is generated in the portion T between thehigh-gray pixel electrode 191 a and the low-gray pixel electrode 191 b.

In an exemplary embodiment of the pixel having the structure of FIG. 16,the texture is generated between the high-gray pixel electrode 191 a andthe low-gray pixel electrode 191 b, and in such an embodiment, thetexture near the outer of the pixel is decreased.

Hereinafter, the texture generated between the high-gray pixel electrode191 a and the low-gray pixel electrode 191 b shown in FIG. 17 will bedescribed in greater detail with reference to FIG. 18.

FIG. 18 is a cross-sectional view of a position where texture isgenerated according to an electric field in an exemplary embodiment of aliquid crystal display according to the invention.

In FIG. 18, ‘High’ means that the high voltage is relatively applied tothe side of the high-gray pixel electrode 191 a. In FIG. 18, low′ meansthat the low voltage is relatively applied to the side of the low-graypixel electrode 191 b.

The liquid crystal molecules are arranged by the high voltage applied tothe high-gray pixel electrode 191 a on the high-gray pixel electrode 191a and are relatively arranged by the low voltage on the low-gray pixelelectrode 191 b. However, in the center of two pixel electrodes, thearrangement direction of the liquid crystal molecule arranged on thehigh-gray pixel electrode 191 a and the arrangement direction of theliquid crystal molecules arranged on the low-gray pixel electrode 191 bmay contact or collide to each other. However, the arrangement directionon the high-gray pixel electrode 191 a applied with the high voltage hasa stronger control force such that the texture is generated at theposition closer to the low-gray pixel electrode 191 b, not the middleposition of two electrodes as shown in FIG. 18.

According to an exemplary embodiment having a pixel structure of FIG.16, the texture generated near the pixel electrode may be reduced.

Hereinafter, exemplary embodiments in which the texture generated at thecenter shown in FIG. 17 is reduced will be described in greater detailwith reference to FIG. 19 to FIG. 22.

FIG. 19 to FIG. 22 are views of texture of exemplary embodiments of apixel electrode having various structures, according to the invention.

In the upper side of each of FIG. 19 to FIG. 22, an exemplary embodimentof the unit pixel electrode included in the high-gray pixel electrode191 a and the unit pixel electrode of the low-gray pixel electrode 191 bare shown. Also, in the lower side of each of FIG. 19 to FIG. 22, thetexture of the unit pixel is shown.

In FIG. 19 to FIG. 22, the change of the texture is shown while changingthe interval between the high-gray pixel electrode 191 a and thelow-gray pixel electrode 191 b in the pixel.

Firstly, in an exemplary embodiment, as shown in FIG. 19, the intervalbetween the unit pixel electrode included in the high-gray pixelelectrode 191 a and the unit pixel electrode of the low-gray pixelelectrode 191 b may be substantially uniform. That is, the distance inthe vertical direction between any parts of the unit pixel electrode issubstantially constant.

In alternative exemplary embodiment, as shown in FIG. 20 to FIG. 22, thedistance between two unit pixel electrodes in the vertical direction mayincrease as being closer to both ends from the center, that is, in adirection away from the center of the display area toward a side of thedisplay area. FIG. 20 shows an exemplary embodiment in which thedistance of the vertical direction between two unit pixel electrodes atboth ends of the display area is longer than the distance of thevertical direction between two unit pixel electrodes in the middleportion or the center of the display area, that is, the referencedistance, by about 1 μm, FIG. 21 shows an exemplary embodiment in whichthe distance of the vertical direction between two unit pixel electrodesat both ends is longer than the reference distance by about 2 μm, andFIG. 22 shows an exemplary embodiment in which the distance of thevertical direction between two unit pixel electrodes at both ends islonger than the reference distance by about 3 μm.

As shown in the texture at the lower side of FIG. 19 to FIG. 22, thetexture is generated smallest in the exemplary embodiment of FIG. 22.Accordingly, in an exemplary embodiment, at least one unit pixelelectrode of the unit pixel electrode of the high-gray pixel electrode191 a and the unit pixel electrode of the low-gray pixel electrode 191 bhas the quadrangular structure, and one of facing sides of the unitpixel electrode of the high-gray pixel electrode 191 a and the unitpixel electrode of the low-gray pixel electrode 191 b may have a curvedline structure or may be a convex side. In such an embodiment, when thecurvature of the convex side becomes greater, the texture may bedecreased. A distance or height difference between the center and bothends of the convex side may be in a range of about zero (0) μm to about3 μm.

In an exemplary embodiment, the high-gray pixel electrode and thelow-gray pixel electrode may have the different voltage levels by usingthe reference voltage line 178, as described above.

Next, an exemplary embodiment, in which the voltage levels of twosubpixel electrodes are changed, will be described with reference to thecircuit diagrams of FIG. 23 to FIG. 27.

FIG. 23 to FIG. 27 are equivalent circuit diagrams of exemplaryembodiments of a pixel according to the invention.

Firstly, a pixel of an exemplary embodiment of the liquid crystaldisplay will be described with reference to FIG. 12.

FIG. 23 is a circuit diagram of an exemplary embodiment of the pixel inwhich the voltages of the different levels are applied to two subpixelelectrodes by using the reference voltage line 178, as described above.

In FIG. 23, the high-gray subpixel is indicated by PXa and the low-graysubpixel is indicated by PXb.

Referring to FIG. 23, an exemplary embodiment of the liquid crystaldisplay according to the invention includes the signal lines such as thegate line 121, the data line 171 and the reference voltage line 178 thattransmits the reference voltage, and the pixels PX connected to thesignal lines.

Each pixel PX includes the first and second subpixels PXa and PXb. Thefirst subpixel PXa includes a first switching element Qa and a firstliquid crystal capacitor Clca, and the second subpixel PXb includessecond and third switching elements Qb and Qc and a second liquidcrystal capacitor Clcb. The first and second thin film transistors Qaand Qb are respectively connected to the gate line 121 and the data line171, and the third thin film transistor Qc is connected to an outputterminal of the second switching element Qb and the reference voltageline 178. An output terminal of the first switching element Qa isconnected to the first liquid crystal capacitor Clca, and the outputterminal of the second switching element Qb is connected to inputterminals of the second liquid crystal capacitor Clcb and the thirdswitching element Qc. The third switching element Qc includes a controlterminal connected to the gate line 121, an input terminal connected tothe second liquid crystal capacitor Clcb, and an output terminalconnected to the reference voltage line 178.

Referring to the operation of the pixel PX shown in FIG. 23, firstly,when the gate line 121 is applied with the gate-on voltage, the firstswitching element Qa, the second switching element Qb and the thirdswitching element Qc connected to the gate line 121 are turned on.Accordingly, the data voltage applied to the data line 171 is applied tothe first liquid crystal capacitor Clca and the second liquid crystalcapacitor Clcb through the turned-on first and second switching elementsQa and Qb such that the first liquid crystal capacitor Clca and thesecond liquid crystal capacitor Clcb are charged by the differencebetween the data voltage and the common voltage. When the first liquidcrystal capacitor Clcb and the second liquid crystal capacitor Clcb areequally applied with the data voltage through the first and secondswitching elements Qa and Qb, the charging voltage of the second liquidcrystal capacitor Clcb is divided through the third switching elementQc. Accordingly, the charging voltage of the second liquid crystalcapacitor Clcb is less than the charging voltage of the first liquidcrystal capacitor Clca such that the luminances of the two subpixels PXaand PXb may be different from each other. Accordingly, by properlycontrolling the voltage charged in the first liquid crystal capacitorClca and the voltage charged in the second liquid crystal capacitorClcb, an image viewed from the side may be substantially close to animage viewed from the front, thereby improving side visibility.

However, the structure of the pixel PX of an exemplary embodiment of theliquid crystal display according to the invention is not limited to theexemplary embodiment shown in FIG. 23, and may be variously modified.

Next, a pixel of an alternative exemplary embodiment of the liquidcrystal display will be described with reference to FIG. 24.

Such an embodiment of the liquid crystal display according to theinvention includes signal lines including a plurality of gate lines GL,a plurality of data lines DL and a plurality of storage electrode linesSL, and a plurality of pixels PX connected thereto. Each pixel PXincludes a pair of first and second subpixels PXa and PXb. The firstsubpixel electrode 191 a is disposed in the first subpixel PXa and thesecond subpixel electrode 191 b is disposed in the second subpixel PXb.

In such an embodiment, each pixel of the liquid crystal display mayfurther include a switching element Q connected to a gate line GL and adata line DL, a first liquid crystal capacitor Clca and a first storagecapacitor Csta that are connected to the switching element Q anddisposed in the first subpixel PXa, and a second liquid crystalcapacitor Clcb and a second storage capacitor Cstb that are connected tothe switching element Q and disposed in the second subpixel PXb, and anauxiliary capacitor Cas disposed between the switching element Q and thesecond liquid crystal capacitor Clcb.

In such an embodiment, the switching element Q, which is athree-terminal element such as a thin film transistor and the like anddisposed in the lower display panel, includes a control terminalconnected to the gate line GL, an input terminal connected to the dataline DL, and an output terminal connected to the first liquid crystalcapacitor Clca, the first storage capacitor Csta and the auxiliarycapacitor Cas.

One terminal of the auxiliary capacitor Cas is connected to an outputterminal of the switching element Q, and the other terminal of theauxiliary capacitor Cas is connected to the second liquid crystalcapacitor Clcb and the second storage capacitor Cstb.

The charged voltage of the second liquid crystal capacitor Clcb is lowerthan the charged voltage of the first liquid crystal capacitor Clca bythe auxiliary capacitor Cas, thereby improving the side visibility ofthe liquid crystal display.

Next, a pixel of another alternative exemplary embodiment of the liquidcrystal display will be described with reference to FIG. 25.

In such an embodiment, the liquid crystal display includes signal linesincluding a plurality of gate lines GLn and GL(n+1), a plurality of datalines DL and a plurality of storage electrode lines SL, and a pluralityof pixels PX connected thereto. Each pixel PX includes a pair of firstand second subpixels PXa and PXb. The first subpixel electrode 191 a isdisposed in the first subpixel PXa and the second subpixel electrode 191b is disposed in the second subpixel PXb.

In such an embodiment, the liquid crystal display may further include afirst switching element Qa and a second switching element Qb that areconnected to a gate line GLn and a data line DL, a first liquid crystalcapacitor Clca and a first storage capacitor Csta that are connected tothe first switching element Qa and formed in the first subpixel PX, asecond liquid crystal capacitor Clcb and a second storage capacitor Cstbthat are connected to the second switching element Qb and disposed inthe second subpixel, a third switching element Qc connected to thesecond switching element Qb and a subsequent gate line GL(n+1), and anauxiliary capacitor Cas connected to the third switching element Qc.

The first and second switching elements Qa and Qb, which arethree-terminal elements such as a thin film transistor, etc. anddisposed in a lower display panel, include control terminals connectedto the gate line GLn, input terminals connected to the data line DL, andoutput terminals connected to the first liquid crystal capacitor Clcaand the first storage capacitor Csta, and the second liquid crystalcapacitor Clcb and the second storage capacitor Cstb, respectively.

The third switching element Qc, which is a three-terminal element suchas a thin film transistor and the like and disposed in the lower displaypanel, includes a control terminal connected to the subsequent gate lineGL(n+1), an input terminal connected to the second liquid crystalcapacitor Clcb, and an output terminal connected to the auxiliarycapacitor Cas.

One terminal of the auxiliary capacitor Cas is connected to the outputterminal of the third switching element Qc, and the other terminal isconnected to a storage electrode line SL.

Hereinafter, an operation of such an embodiment of the liquid crystaldisplay will be described. When a gate-on voltage is applied to the gateline GLn, the first and second switching elements Qa and Qb that areconnected to the gate line GLn are turned on, and a data voltage of thedata line 171 is applied to the first and second subpixel electrodesthrough the turned-on first and second switching elements Qa and Qb.

Subsequently, when a gate-off voltage is applied to the gate line GLnand the gate-on voltage is applied to the subsequent gate line GL(n+1),the first and second switching elements Qa and Qb are turned off and thethird switching element Qc is turned on. As a result, electrical chargesof the second subpixel electrode (191 b of FIG. 6) connected to theoutput terminal of the second switching element Qb flow into theauxiliary capacitor Cas such that the voltage of the second liquidcrystal capacitor Clcb is decreased.

As described above, in such an embodiment, the charged voltages of thefirst and second liquid crystal capacitors Clca and Clcb are differentfrom each other, thereby improving the side visibility of the liquidcrystal display.

Next, a pixel of another alternative exemplary embodiment of the liquidcrystal display will be described with reference to FIG. 26.

An exemplary embodiment of the liquid crystal display according to theinvention includes the signal lines such as a plurality of gate linesGL, a plurality of data lines DL1 and DL2, and a plurality of storageelectrode lines SL, and a plurality of pixels PX connected thereto. Eachpixel PX includes a pair of first and second liquid crystal capacitorsClca and Clab and a pair of first and second storage capacitors Csta andCstb.

In such an embodiment, each subpixel of the pixel PX includes one liquidcrystal capacitor and one storage capacitor in addition to one thin filmtransistor Q. The thin film transistors Q of two subpixels included inone pixel are connected to the gate lines GL, and connected to differentdata lines (e.g., two adjacent data lines) DL1 and DL2, respectively.The different data lines DL1 and DL2 simultaneously apply the voltagesof the different levels such that the first and second liquid crystalcapacitors Clca and Clcb of two subpixels have different chargedvoltages. As a result, in such an embodiment, the lateral visibility ofthe liquid crystal display may be improved.

Next, a pixel of another alternative exemplary embodiment of the liquidcrystal display will be described with reference to FIG. 27.

In an exemplary embodiment, as shown in FIG. 27, the liquid crystaldisplay includes the gate line GL, the data line DL, a first power lineSL1, a second power line SL2, and the first and second switchingelements Qa and Qb connected to the gate line GL and the data line DL.

In such an embodiment, the liquid crystal display further includes anassistance step-up capacitor Csa and the first liquid crystal capacitorClca connected to the first switching element Qa, and an assistancestep-down capacitor Csb and the second liquid crystal capacitor Clcbconnected to the second switching element Qb.

The first switching element Qa and the second switching element Qb maybe the three-terminal elements such as the thin film transistor. Thefirst switching element Qa and the second switching element Qb areconnected to the same gate line GL and the same data line DL to beturned on such that the same data signals are output thereto at the sametime.

A voltage that swings in a constant period is applied to the first powerline SL1 and the second power line SL2. The first power line SL1 isapplied with a first low voltage during a predetermined period or afirst period (for example, a horizontal period), and is applied with afirst high voltage during a next predetermined period or a secondperiod. The second power line SL2 is applied with a second high voltageduring the predetermined period or the first period, and is applied witha second low voltage during the next predetermined period or the secondperiod. In such an embodiment, the first period and the second periodare set repeatedly (e.g., alternately or several times) during oneframe, such that the voltage that swings is applied to the first powerline SL1 and the second power line SL2. In such an embodiment, the firstlow voltage and the second low voltage may be substantially the same aseach other, and the first high voltage and the second high voltage maybe substantially the same as each other.

The assistance step-up capacitor Csa is connected to the first switchingelement Qa and the first power line SL1, and the assistance step-downcapacitor Csb is connected to the second switching element Qb and thesecond power line SL2.

A voltage Va of a terminal (hereinafter referred to as a “firstterminal”) through which the assistance step-up capacitor Csa isconnected to the first switching element Qa is decreased when the firstpower line SL1 is applied with the first low voltage, and the voltage Vaof the first terminal is increased when the first power line SL1 isapplied with the first high voltage. Then, the voltage Va of the firstterminal swings according to the swing of the voltage of the first powerline SL1.

In such an embodiment, a voltage Vb of a terminal (hereinafter referredto as a “second terminal”) through which the assistance step-downcapacitor Csb is connected to the first switching element Qb isincreased when the second power line SL2 is applied with the second highvoltage, and the voltage Vb of the second terminal is decreased when thesecond power line SL2 is applied with the second low voltage. Then, thevoltage Vb of the second terminal swings according to the swing of thevoltage of the second power line SL2.

As described above, in an exemplary embodiment, two subpixels areapplied with the same data voltage, and the voltages Va and Vb of thepixel electrodes of two subpixels becomes different from each otheraccording to the magnitude of the voltages swung in the first and secondpower lines SL1 and SL2 such that the transmittance of the two subpixelsis set differently from each other, thereby improving the lateralvisibility.

In an exemplary embodiment, as shown in FIG. 24 to FIG. 27, thereference voltage line is used, but not being limited thereto. In anexemplary embodiment of the invention, any line parallel to the dataline and passing the center of the display area of the pixel in thelongitudinal direction may be used to improve the display quality.

In exemplary embodiments of the liquid crystal display, the unit pixelelectrode included in the pixel electrode has the minute branches 199and the number of the unit pixel electrodes is substantially great suchthat the number of the minute branches 199 in the pixel electrode issubstantially great. As a result, in such embodiments, the liquidcrystal control force to control the liquid crystal molecule may besufficiently obtained such that a prepolymer polymerized by a separatelight may be omitted in the liquid crystal layer.

However, according to an alternative exemplary embodiment, the liquidcrystal control force may be partially decreased such that theprepolymer may be included in the liquid crystal layer.

An exemplary embodiment of a method of forming the pretilt in a liquidcrystal layer including the prepolymer will be described with referenceto FIG. 28.

FIG. 28 is a view showing an exemplary embodiment of a process ofproviding a pretilt angle to liquid crystal molecules using prepolymerspolarized by light such as ultraviolet rays.

Referring to FIG. 28, first, prepolymers 330 such as monomers, which iscured by polymerization by rays such as ultraviolet rays, and liquidcrystal materials are injected together between two display panels,e.g., a lower panel 100 and an upper panel 200, of a liquid crystaldisplay. The prepolymer 330 may be a reactive mesogen that ispolymerized by rays such as ultraviolet rays.

Next, the data voltage is applied to the first and second subpixelelectrodes, and a common voltage is applied to the common electrode ofthe upper panel 200, thereby generating the electric field in a liquidcrystal layer 3 between the two display panels 100 and 200. Thus, theliquid crystal molecules 31 of the liquid crystal layer 3 are inclinedin a predetermined direction in response to the electric field.

As described above, when light, e.g., the ultraviolet rays, isirradiated in the state that the liquid crystal molecules 31 of theliquid crystal layer 3 are inclined in the predetermined direction, theprepolymer 330 is polymerized, and as shown in FIG. 28, a pretiltproviding polymer 350 is formed. The pretilt providing polymer 350contacts the two display panels 100 and 200. The liquid crystalmolecules 31 are determined to have the alignment direction in theabove-described direction with the pretilt angle by the pretiltproviding polymer 350. Accordingly, in the state that the voltage is notapplied to the field generating electrodes, e.g., the pixel electrodeand the common electrode, the liquid crystal molecules 31 are arrangedwith the pretilt angle in four directions.

As a result, the liquid crystal molecules 31 have the pretilt angle infour directions in each region of the upper and lower subpixels in apixel.

In an exemplary embodiment, the pretilt using the polymer as shown inFIG. 28 is additionally applied such that the texture may be furtherreduced together with the control by the liquid crystal control forceprovided by the minute branches 199.

In an exemplary embodiment, as described with reference to FIG. 28, theliquid crystal layer includes the photo-reactive material, but not beinglimited thereto. In an alternative exemplary embodiment, the alignmentlayer may include the photo-reactive material.

While the invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A liquid crystal display comprising: aninsulation substrate; a plurality of pixels formed on the insulationsubstrate, wherein each pixel has a shape elongated in a horizontaldirection and comprises a thin film transistor formation region and adisplay area; and a reference voltage line extending in a verticaldirection along a center of the display area, wherein the display areacomprises a plurality of domains arranged in two rows, the domains in afirst row of the two rows define a high-gray subpixel area of thedisplay area, the domains in a second row of the two rows define alow-gray subpixel area of the display area, and the reference voltageline comprises a branch extending toward the thin film transistorformation region along an outer region of the display area.
 2. Theliquid crystal display of claim 1, further comprising: a first thin filmtransistor connected to a high-gray pixel electrode disposed in thehigh-gray subpixel area; a second thin film transistor connected to alow-gray pixel electrode disposed in the low-gray subpixel area; and athird thin film transistor connected to the low-gray pixel electrode andthe reference voltage line.
 3. The liquid crystal display of claim 2,wherein each of the high-gray subpixel area and the low-gray subpixelarea comprises six domains.
 4. The liquid crystal display of claim 3,wherein the reference voltage line crosses a center of the high-graysubpixel area and the low-gray subpixel area.
 5. The liquid crystaldisplay of claim 2, wherein the high-gray pixel electrode comprises aplurality of unit pixel electrodes corresponding to the domains in thehigh-gray pixel area, the low-gray pixel electrode comprises a pluralityof unit pixel electrodes corresponding to the domains in the low-graypixel area, one of the unit pixel electrodes of the high-gray pixelelectrode in the high-gray subpixel area and one of the unit pixelelectrodes of the low-gray pixel electrode in the low-gray subpixel areaare disposed adjacent to each other in the vertical direction, and adistance between the unit pixel electrodes disposed adjacent to eachother in the vertical direction is uniform.
 6. The liquid crystaldisplay of claim 2, wherein the high-gray pixel electrode comprises aplurality of unit pixel electrodes corresponding to the domains in thehigh-gray pixel area, the low-gray pixel electrode comprises a pluralityof unit pixel electrodes corresponding to the domains in the low-graypixel area, one of the unit pixel electrodes of the high-gray pixelelectrode in the high-gray subpixel area and one of the unit pixelelectrodes of the low-gray pixel electrode in the low-gray subpixel areaare disposed adjacent to each other in the vertical direction, and adistance between the unit pixel electrodes disposed adjacent to eachother in the vertical direction increases in a direction away from thecenter of the display area toward a side of the display area.
 7. Theliquid crystal display of claim 6, wherein a difference between thedistance between the unit pixel electrodes disposed adjacent to eachother in the vertical direction at the center of the display area andthe distance between the unit pixel electrodes disposed adjacent to eachother in the vertical direction at the side of the display area is in arange of about zero (0) micrometer to about 3 micrometers.
 8. The liquidcrystal display of claim 2, wherein each of the high-gray pixelelectrode and the low-gray pixel electrode comprises a plurality of unitpixel electrodes, each of the unit pixel electrodes comprise a centerelectrode having a plane shape and a plurality of minute branchesextending from a side of the center electrode, each of the high-graysubpixel area and the low-gray subpixel area comprises a commonelectrode facing the unit pixel electrodes thereof, and an opening isdefined in the common electrode.